Fuel Pump Control Module, Checking

Special tools and workshop equipment required 

• multimeter
• Wiring diagram.

Test requirements 

• Fuse -SC3- OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, selector lever in position "P" or "N".
• A/C switched off.
• Ground (GND) connections between engine/transmission/chassis OK.
• Ignition switched off.

Test procedure 

-- Perform a preliminary check to verify the customer's complaint. Refer to PRELIMINARY CHECK 

Start diagnosis 

-- Remove rear seat assembly. Refer to the appropriate service information

Checking voltage 

Switch the ignition on.

-- Using a multimeter, check the following wiring connection for voltage.

Fuel Pump (FP) Control Module J538 Terminal	Measure to
T5f/4	B+
T5f/3	Chassis Ground (GND)

Specified value: Battery voltage

-- Switch the ignition off.

If the specified value was not obtained:

-- Check the Fuel Pump (FP) Control Module -J538- wiring harness terminal T5f/3 to the Battery -- B (+) terminal for an open circuit or short to Ground (GND).

-- Check the Fuel Pump (FP) Control Module -J538- wiring harness terminal T5f/4 to GND for an open circuit or short to B+.

-- Check the electrical harness connectors for damage, corrosion, loose or broken terminals.

-- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring:

-- Switch the ignition on.

-- Using a multimeter, check the following wiring connection for voltage.

Fuel Pump (FP) Control Module J538 Terminal	Measure to
T5f/3	Chassis Ground (GND)

Specified value: about 12.5 V

-- Switch the ignition off.

If the specified value was not obtained:

-- Check the Fuel Pump (FP) Control Module -J538- wiring harness terminal T5f/5 to harness connector terminal T94 /30 for an open circuit or short to Ground (GND).

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring:

Checking Ground (GND)

-- Using a multimeter, check the Fuel Pump (FP) Control Module -J538- wiring harness terminal T10k/2 to chassis ground for resistance.

Fuel Pump (FP) Control Module J538 Terminal	Measure to Engine Control Module (ECM) -J623-
T5f/5	T94/30

Specified value: 1.5 Ω maximum.

If the specified value was not obtained:

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring and the voltage supply was OK:

-- Replace the Fuel Pump (FP) Control Module -J538-. Refer to the appropriate service information.

-- Perform a road test to verify repair.

If the fault does not return:

Repair complete, Generate readiness code. Refer to READINESS CODE .

-- End diagnosis.

If the fault does return and no malfunction is detected in the wiring and the voltage supply was OK:

-- Replace the Engine Control Module (ECM) -J623-. Refer to the appropriate service information.

-- Assembly is performed in the reverse of the removal.

Final procedures 

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .